Why Don’t Systems Die? An Escalation of Commitment Perspective

Legacy systems, using obsolete technologies, which are costly to maintain and which constrain users abound. Yet these systems persist and decision makers continue to allocate them resources despite better alternatives. Our research focuses on why such declining systems are not retired or replaced despite evidence that they have outlived their utility. IS research has studied such escalation of commitment but in the context of failing Information Systems Development (ISD) projects. While on the surface declining systems and failing ISD projects seem similar, important contextual differences imply that extant theorizing for failing projects is insufficient to understand the factors influencing persistence with declining systems. Our research contextualizes and extends escalation of commitment research to (a) understand factors influencing persistence with declining systems, and (b) extend the boundaries of current theory beyond the ISD context by redefining antecedents and hypothesizing their effects at later system lifecycle stages

Effect of App Market Conditions on Permissions Usage by App Developers

The common mechanism for controlling security and privacy data on mobile platforms is through the app permissions model. Platform owners evolve the model through changes to the APIs provided to app developers. This however places increased responsibility on app developers to determine the privileges they need to deliver the app’s functionality. In this paper, we investigate the factors influencing an app developer to seek permissions for privileged access in the context of the Android mobile platform. We find that the apps facing higher competition in their category or targeted at more mature audiences seek more permissions from users. However, apps charging higher prices for downloads ask for a lower number of permissions. The findings suggest that market conditions incentivize app developers to seek more privileges whereas a revenue stream such as download price does not. Therefore, more control exercised by the platform owner on the conditions of their app market would be more beneficial to the platform from the security and privacy perspective

Care gaps and recommendations in vestibular migraine: An expert panel summit

Vestibular migraine (VM) is an increasingly recognized pathology yet remains as an underdiagnosed cause of vestibular disorders. While current diagnostic criteria are codified in the 2012 Barany Society document and included in the third edition of the international classification of headache disorders, the pathophysiology of this disorder is still elusive. The Association for Migraine Disorders hosted a multidisciplinary, international expert workshop in October 2020 and identified seven current care gaps that the scientific community needs to resolve, including a better understanding of the range of symptoms and phenotypes of VM, the lack of a diagnostic marker, a better understanding of pathophysiologic mechanisms, as well as the lack of clear recommendations for interventions (nonpharmacologic and pharmacologic) and finally, the need for specific outcome measures that will guide clinicians as well as research into the efficacy of interventions. The expert group issued several recommendations to address those areas including establishing a global VM registry, creating an improved diagnostic algorithm using available vestibular tests as well as others that are in development, conducting appropriate trials of high quality to validate current clinically available treatment and fostering collaborative efforts to elucidate the pathophysiologic mechanisms underlying VM, specifically the role of the trigemino-vascular pathways

The renormalization group for correlated scales: one-stage versus two-stage running

Nonrelativistic bound states have two low energy scales, a soft scale mu_S of order mv and an ultrasoft scale mu_U of order mv^2. In two-stage running, the soft and ultrasoft scales are lowered from m to mv, and then the ultrasoft scale is lowered from mv to mv^2. In one-stage running, the two scales are lowered in a correlated way using a subtraction velocity. We compare these two methods of summing logarithms and show that only the correlated running in velocity space of the one-stage method correctly reproduces the logarithms in non-relativistic bound states in QED. The argument for one-stage running is general, and should apply to any system with correlated scales.Comment: 9 pages, typos fixed, results and conclusions unchange

Achieving Performance Objectives for Database Workloads

In this thesis, our goal is to achieve customer-specified performance objectives for workloads in a database management system (DBMS). Competing workloads in current DBMSs have detrimental effects on performance. Differentiated levels of service become important to ensure that critical work takes priority. We design a feedback-based admission differentiation framework, which consists of three components: workload classifier, workload monitor and adaptive admission controller. The adaptive admission controller uses the workload management capabilities of IBM DB2’s Workload Manager (WLM) to achieve the performance objectives of the most important workload by applying admission control on the rest of the work, which is less important and may or may not have performance objectives. The controller uses a feedback-based technique to automatically adjust the admission control on the less important work to achieve performance objectives for the important workload. The adaptive admission controller is implemented on an instance of DB2 to the test the effectiveness of the controller

Synthesis and characterization of new fatty Schiff base ethers of 4-((pyridin-3-ylmethylimino)methyl)phenol

A series of ten new Schiff base ethers were synthesized by etherification of Schiff base-{4-(pyridine-3-methylimino) methyl phenol} with fatty alkyl bromides of different chain lengths (C4-C18) in the presence of base with 80-85% isolated yields. All the synthesized Schiff base ethers (2a-j) were characterized by FT-IR, 1H NMR, 13C NMR and Mass spectral studies. Presence of a characteristic peak for ether linkage, C-O at 1039 cm-1 in IR spectra; a triplet around 7.67 ppm in 1H NMR and a characteristic peak around 69.7 in case of  13C NMR further confirmed the structures of Schiff base ethers. The structure of all the compounds were further confirmed by their characteristic molecular ion peaks in ESI-MS

Synthesis of industrially important platform chemicals via olefin metathesis of palash fatty acid methyl esters

The study signifies the importance of olefin metathesis in developing industrially important platform chemicals from a non-edible renewable resource, palash oil using Grubb’s second generation catalyst. The reaction conditions were optimized by varying the concentration of the catalyst, 0.03-0.05 mM and the temperature, 45-100 °C of the reaction. Maximum yield of the metathesized products, as analysed using GC/GC-MS were obtained employing lower concentration of the catalyst, 0.03 Mm and temperature, 45 °C for 36 h. The metathesized products showed the formation of hydrocarbons namely 9-octadecene (10.9%) and cyclodecacyclotetradecene (27%) as major. The formation of cyclodecacyclotetradecene was observed for the first time. The study also describes the possible routes and the molecules involved in the formation of the metathesized products

Metathesis of 9-octadecenoic acid methyl ester: diversity and mechanism of product formation at various Grubbs’ catalyst concentrations

Self-metathesis of 9-octadecenoic acid methyl ester was carried out with varying the concentration of Grubbs’ second generation catalyst from 0.03 mmol to 0.18 mmol at 40-45 °C for 36 h. Only two products (9-octadecene 30%, and dimethyl-9-octadecene-dienoate 23%) resulted when 0.06 mmol of catalyst was employed, while at other concentrations four metathesized products were observed. 9-Octadecene generated at 0.03, 0.06 and 0.12 mmol completely disappeared and dimethyl-9-octadecene-dienoate (64%) was observed in major amounts at 0.18 mmol concentration

Development And Validation Of Integrated Design Framework For Compressor System Model

The performance of a refrigerator is largely guided by the efficiency of its drive unit, namely, the compressor & understanding the compressor behavior requires a detailed study of its dynamics, flow-thermals, electrical and controls aspects. Having a simulation model which captures these physics reasonably well is a critical part of the design and performance prediction of a compressor. The current paper describes a systematic approach of making a system level simulation framework by first developing individual models and then integrating them into a single framework to capture the multi-physics interaction of the different sub-components. This framework, developed in MATLAB/SIMULINK contains five modules, namely, Dynamics, Thermal, Motor, Controls and Post-processor. Dynamics is modeled as a spring-mass system with adjustable static equilibrium and head-crash prevention algorithm. The thermodynamics model essentially captures the valve physics. The valves in a reciprocating compressor contribute to pressure losses (pressure profile deviation from ideal suction & discharge processes, valve dynamics, leakages, pressure pulsations) and thermal losses (refrigerant back-flow caused by incorrect valve timing). The starting point of simulating these details is considering the gas dynamics and coupling it to the valve motion. The prediction of this model is validated against test data of a baseline compressor. As part of the integrated design framework, a permanent magnet motor is simulated as a resistance-inductance network with a series, velocity dependent voltage. To impress the desired operating conditions (capacity, stroke, clearance etc.) upon the integrated system model, a set of controllers were designed to control the motor

Evidence for the absence of regularization corrections to the partial-wave renormalization procedure in one-loop self energy calculations in external fields

The equivalence of the covariant renormalization and the partial-wave renormaliz ation (PWR) approach is proven explicitly for the one-loop self-energy correction (SE) of a bound electron state in the presence of external perturbation potentials. No spurious correctio n terms to the noncovariant PWR scheme are generated for Coulomb-type screening potentia ls and for external magnetic fields. It is shown that in numerical calculations of the SE with Coulombic perturbation potential spurious terms result from an improper treatment of the unphysical high-energy contribution. A method for performing the PWR utilizing the relativistic B-spline approach for the construction of the Dirac spectrum in external magnetic fields is proposed. This method is applied for calculating QED corrections to the bound-electron $g$-factor in H-like ions. Within the level of accuracy of about 0.1% no spurious terms are generated in numerical calculations of the SE in magnetic fields.Comment: 22 pages, LaTeX, 1 figur